The plot's one of my main reasons for replaying any FF game - seeing again how it all unfolded, this time knowing how it's actually going to turn out. Quite a different experience to that first play-through, when there's still that pall of mystery.
Understanding the gameplay better makes it a more enjoyable experience the second time around too. Knowing how battles, abilities etc all work.
And without the pressing desire to keep advancing the plot, there's more time for exploring and sight-seeing.